The present invention relates to an antenna device adapted to be mounted on a vehicle body and in which an antenna body is pivotably provided.
FIG. 5 shows an example of this kind of antenna device which is disclosed in Japanese Patent Publication No. 2003-32015A.
A single plate-shaped first feeder plate 14 which is electrically connected to the proximal end of an antenna element 12 is disposed in a proximal end portion of a pivotable antenna body 10. The first feeder plate 14 is conductive and elastic. A single plate-shaped second feeder plate 18 is disposed in a base member 16. The second feeder plate 18 is conductive. A terminal portion 18a projecting from the second feeder plate 18 is electrically connected in a proper manner to a circuit board 20 which is provided in the base member 16.
A shaft 22 is made to penetrate through the first and second feeder plates 14 and 18 in a state that they are opposed to each other, whereby the first feeder plate 14 is pivotable with respect to the second feeder plate 18. A coiled spring 24 is inserted to the shaft 22 so that the first feeder plate 14 is kept in elastic contact with the second feeder plate 18. The elastic contact faces of the first and second feeder plates 14 and 18 are formed with a recess and a projection, respectively, that can be rendered in a fitting relationship and thereby constitute a click mechanism.
In the above structure, electrical conduction is established between the proximal end of the antenna element 12 and the circuit board 20 via the first and second feeder plates 14 and 18. Since the recess and projection of the first and second feeder plates 14 and 18 are rendered in a fitting relationship or separated from each other, the antenna body 10 can be pivoted with respect to the base member 16 and fixedly held by the latter in a prescribed posture.
However, the coiled spring 24 is necessary for keeping the first and second feeder plates 14 and 18 in elastic contact with each other and the number of parts is increased accordingly. In addition, assembling work needs to be performed in a state that the coiled spring 24 is compressed and the work is complicated. Further, since elastic contact and electric conduction between the first and second feeder plates 14 and 18 are established by the single pair of faces, the stability of electrical connection is not always satisfactory.